A heel is the bottom, back part of a shoe or boot that provides elevation. The styling and construction of a heel may vary (i.e., stacked, stilletto, spiked, sculptured, kitten).
About Metal:
Metal is a strong, shiny material that can be molded and shaped in any way and is often used as a decorative ornament in garments and footwear.
About Oxfords:
Oxfords are any styling of shoe, which features enclosed lacing with typically four to five eyelets.